enum Season{
  spring,
  summer,
  autumn,
  winter
}

void main(){
  var season=Season.autumn;
  print(season.index);
  switch(season){
    case Season.spring:
      print('3~5');
      break;
    case Season.summer:
      print('6~8');
      break;
    case Season.autumn:
      print('9~11');
      break;
    case Season.winter:
      print('12~2');
      break;
    default:
      print('?');
  }
}
